C++ (Cpp) bondAngleRadians Examples

Example #1

File: oplscalculation.cpp Project: de4sh/chemkit

chemkit::Float OplsAngleBendCalculation::energy() const
{
    const chemkit::ForceFieldAtom *a = atom(0);
    const chemkit::ForceFieldAtom *b = atom(1);
    const chemkit::ForceFieldAtom *c = atom(2);

    chemkit::Float ka = parameter(0);
    chemkit::Float theta0 = parameter(1);

    chemkit::Float theta = bondAngleRadians(a, b, c);

    return ka * pow(theta - theta0, 2);
}

Example #2

File: uffcalculation.cpp Project: armando-2011/chemkit

chemkit::Real UffAngleBendCalculation::energy() const
{
    const chemkit::ForceFieldAtom *a = atom(0);
    const chemkit::ForceFieldAtom *b = atom(1);
    const chemkit::ForceFieldAtom *c = atom(2);

    chemkit::Real ka = parameter(0);
    chemkit::Real c0 = parameter(1);
    chemkit::Real c1 = parameter(2);
    chemkit::Real c2 = parameter(3);

    chemkit::Real theta = bondAngleRadians(a, b, c);

    return ka * (c0 + (c1 * cos(theta)) + (c2 * cos(2*theta)));
}

Example #3

File: oplscalculation.cpp Project: de4sh/chemkit

std::vector<chemkit::Vector3> OplsAngleBendCalculation::gradient() const
{
    const chemkit::ForceFieldAtom *a = atom(0);
    const chemkit::ForceFieldAtom *b = atom(1);
    const chemkit::ForceFieldAtom *c = atom(2);

    chemkit::Float ka = parameter(0);
    chemkit::Float theta0 = parameter(1);

    chemkit::Float theta = bondAngleRadians(a, b, c);

    std::vector<chemkit::Vector3> gradient = bondAngleGradientRadians(a, b, c);

    // dE/dtheta
    chemkit::Float de_dtheta = (2.0 * ka * (theta - theta0));

    gradient[0] *= de_dtheta;
    gradient[1] *= de_dtheta;
    gradient[2] *= de_dtheta;

    return gradient;
}

Example #4

File: uffcalculation.cpp Project: armando-2011/chemkit

std::vector<chemkit::Vector3> UffAngleBendCalculation::gradient() const
{
    const chemkit::ForceFieldAtom *a = atom(0);
    const chemkit::ForceFieldAtom *b = atom(1);
    const chemkit::ForceFieldAtom *c = atom(2);

    chemkit::Real ka = parameter(0);
    chemkit::Real c1 = parameter(2);
    chemkit::Real c2 = parameter(3);

    chemkit::Real theta = bondAngleRadians(a, b, c);

    // dE/dtheta
    chemkit::Real de_dtheta = -ka * (c1 * sin(theta) + 2 * c2 * sin(2 * theta));

    std::vector<chemkit::Vector3> gradient = bondAngleGradientRadians(a, b, c);

    gradient[0] *= de_dtheta;
    gradient[1] *= de_dtheta;
    gradient[2] *= de_dtheta;

    return gradient;
}